| 1. |
- Bull, Cecilia, 1977, et al.
(författare)
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A novel mouse model of radiation-induced cancer survivorship diseases of the gut
- 2017
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Ingår i: American journal of physiology. Gastrointestinal and liver physiology. - : American Physiological Society. - 1522-1547 .- 0193-1857. ; 313:5, s. G456-G466
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Tidskriftsartikel (refereegranskat)abstract
- A deeper understanding of the radiation-induced pathophysiological processes that develop in the gut is imperative to prevent, alleviate, or eliminate cancer survivorship diseases after radiotherapy to the pelvic area. Most rodent models of high-dose gastrointestinal radiation injury are limited by high mortality. We therefore established a model that allows for the delivering of radiation in fractions at high doses while maintaining long-term survival. Adult male C57/BL6 mice were exposed to small-field irradiation, restricted to 1.5 cm of the colorectum using a linear accelerator. Each mouse received 6 or 8 Gy, two times daily in 12-h intervals in two, three, or four fractions. Acute cell death was examined at 4.5 h postirradiation and histological changes at 6 wk postirradiation. Another group was given four fractions of 8 Gy and followed over time for development of visible symptoms. Irradiation caused immediate cell death, mainly limited to the colorectum. At 6 wk postirradiation, several crypts displayed signs of radiation-induced degeneration. The degenerating crypts were seen alongside crypts that appeared perfectly healthy. Crypt survival was reduced after the fourth fraction regardless of dose, whereas the number of macrophages increased. Angiogenesis was induced, likely as a compensatory mechanism for hypoxia. Four months postirradiation, mice began to show radiation-induced symptoms, and histological examination revealed an extensive crypt loss and fibrosis. Our model is uniquely suitable for studying the long-term trajectory and underlying mechanisms of radiation-induced gastrointestinal injury. NEW & NOTEWORTHY A novel mouse model for studying the long-term trajectory of radiation-induced gut injury. The method allows for the use of high doses and multiple fractions, with minor impact on animal health for at least 3 mo. Crypt loss and a slow progression of fibrosis is observed. Crypt degeneration is a process restricted to isolated crypts. Crypt degeneration is presented as a convenient proxy endpoint for long-term radiation-induced gut injury.
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| 2. |
- Bull, Cecilia, 1977, et al.
(författare)
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Intra-abdominal Surgery and Intestinal Syndromes After Pelvic Radiation Therapy
- 2024
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Ingår i: ADVANCES IN RADIATION ONCOLOGY. - 2452-1094. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To determine the effects of intra-abdominal surgery on the intensities of 5 radiation -induced intestinal syndromes in survivors of pelvic cancer. Methods and Materials: The analysis included 623 women born in 1927 or later who had survived cancer. They all had received external radiation therapy toward the pelvic area to treat gynecologic cancers. Information from 344 women who did not undergo irradiation, matched for age and residency, was also included. Main outcome measures after the surgical procedures were the intensity scores for 5 radiation -induced intestinal syndromes: urgency-tenesmus syndrome, fecal -leakage syndrome, excessive mucus discharge, excessive gas discharge, and blood discharge. The scores were based on symptom frequencies obtained from patient -reported outcomes and on factor loadings obtained from a previously reported factor analysis. Follow-up was 2 to 15 years after radiation therapy. Results: Among survivors of cancer, intra-abdominal surgery increased the intensity of the urgency-tenesmus syndrome, the fecalleakage syndrome, excessive gas discharge, and blood discharge but had a negligible effect on mucus discharge. Intra-abdominal surgery had an especially negative effect on the urgency-tenesmus syndrome. Although the combination of appendectomy with 1 or more other intra-abdominal surgeries resulted in the highest score for all syndromes, appendectomy alone had weak to no effect. In women who did not undergo irradiation, a similar pattern was seen, albeit with much lower scores. Conclusions: We found intra-abdominal surgery to be a risk factor among survivors of gynecologic cancer, increasing the intensity score of 4 out of 5 radiation -induced intestinal syndromes. During radiation therapy, it may be worthwhile to pay extra attention to the dose of unwanted ionizing radiation to the intestines if the patient previously has undergone intra-abdominal surgery.
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| 3. |
- Devarakonda, Sravani, et al.
(författare)
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Dietary Fiber and the Hippocampal Neurogenic Niche in a Model of Pelvic Radiotherapy
- 2021
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522. ; 475, s. 137-147
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Tidskriftsartikel (refereegranskat)abstract
- sought to determine whether radiation to the colorectum had an impact on parameters of hippocampal neurogenesis and, if so, whether it could be modulated by a fiber-rich diet. Male C57BL/6J mice were fed a diet containing bioprocessed oat bran or a fiber-free diet, starting two weeks before colorectal irradiation with 4 fractions of 8 Gray or sham-irradiation. Diets were then continued for 1, 6 or 18 weeks, whereafter parameters of hippocampal neurogenesis were analyzed and correlated to serum cytokine levels. No statistically significant changes in neuronal markers or cell proliferation were found at one week post-irradiation. Six weeks postirradiation there was a decreased cell proliferation in the subgranular zone that appeared slightly more pronounced in irradiated animals on a fiber-free diet and increased numbers of immature neurons per mm2 dentate gyrus in the irradiated mice, with a statistically significant increase in mice on a fiber-rich diet. Microglial abundancy was similar between all groups. 18 weeks post-irradiation, a fiber-free diet had reduced the number of immature neurons, whereas irradiation resulted in an increase. Despite this, the population of mature neurons was stable. Analysis of serum cytokines revealed a negative correlation between MIP1-a and the number of immature neurons one week after irradiation, regardless of diet. Our findings show that pelvic radiotherapy has the potential to cause a long-lasting impact on hippocampal neurogenesis, and dietary interventions may modulate this impact. More in-depth studies on the relationship between irradiation-induced intestinal injury and brain health are warranted. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of IBRO. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 4. |
- Malipatlolla, Dilip, 1990, et al.
(författare)
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A fiber-rich diet and radiation-induced injury in the murine intestinal mucosa
- 2022
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Dietary fiber is considered a strong intestinal protector, but we do not know whether dietary fiber protects against the long-lasting mucosal damage caused by ionizing radiation. To evaluate whether a fiber-rich diet can ameliorate the long-lasting pathophysiological hallmarks of the irradiated mucosa, C57BL/6J mice on a fiber-rich bioprocessed oat bran diet or a fiber-free diet received 32 Gray in four fractions to the distal colorectum using a linear accelerator and continued on the diets for one, six or 18 weeks. We quantified degenerating crypts, crypt fission, cell proliferation, crypt survival, macrophage density and bacterial infiltration. Crypt loss through crypt degeneration only occurred in the irradiated mice. Initially, it was most frequent in the fiber-deprived group but declined to levels similar to the fiber-consuming group by 18 weeks. The fiber-consuming group had a fast response to irradiation, with crypt fission for growth or healing peaking already at one week post-irradiation, while crypt fission in the fiber-deprived group peaked at six weeks. A fiber-rich diet allowed for a more intense crypt cell proliferation, but the recovery of crypts was eventually lost by 18 weeks. Bacterial infiltration was a late phenomenon, evident in the fiber-deprived animals and intensified manyfold after irradiation. Bacterial infiltration also coincided with a specific proinflammatory serum cytokine profile. In contrast, mice on a fiber-rich diet were completely protected from irradiation-induced bacterial infiltration and exhibited a similar serum cytokine profile as sham-irradiated mice on a fiber-rich diet. Our findings provide ample evidence that dietary fiber consumption modifies the onset, timing and intensity of radiation-induced pathophysiological processes in the intestinal mucosa. However, we need more knowledge, not least from clinical studies, before this finding can be introduced to a new and refined clinical practice.
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| 5. |
- Malipatlolla, Dilip, 1990, et al.
(författare)
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Long-term mucosal injury and repair in a murine model of pelvic radiotherapy
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Chronic intestinal injury after pelvic radiotherapy affects countless cancer survivors worldwide. A comprehensive understanding of the long-term injury dynamics is prevented in available animal models. With linear accelerators that are used to treat cancer in patients, we irradiated a small volume encompassing the colorectum in mice with four fractions of 8 Gy per fraction. We then determined the long-term dynamics of mucosal injury, repair, and the duration of inflammation. We show that crypt fission, not cell proliferation, is the main long-term mechanism for rescuing crypt density after irradiation, and provides a potentially wide window for clinical interventions. Persisting macrophage aggregations indicate a chronic mucosal inflammation. A better understanding as to how crypt fission is triggered and why it fails to repair fully the mucosa may help restore bowel health after pelvic radiotherapy. Moreover, anti-inflammatory interventions, even if implemented long after completed radiotherapy, could promote bowel health in pelvic cancer survivors.
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| 6. |
- Malipatlolla, Dilip, 1990
(författare)
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Understanding normal-tissue late effects in the intestines after pelvic radiotherapy
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Radiotherapy cures patients from deadly cancer, alone or in combination with other treatments. The photons must pass through normal tissue to converge on the tumor, and it is unavoidable that radiotherapy causes acute as well as late adverse effects. Roughly one million cancer survivors in Europe are suffering from radiation-induced intestinal symptoms, such as urgency to defecate, leakage of feces and mucus, bleeding, and excessive odorous gas discharge. The symptoms can appear weeks to years after the treatment and severely reduce the quality of life. Very little is known about how radiation-induced pathological processes progress over time and how various factors such as diet influence the disease course. To better understand the dynamics of intestinal injury after radiotherapy, we have developed a novel mouse model of pelvic radiotherapy and determined the injury and repair mechanisms over time. In the study for Paper I, we used the clinic's linear accelerator to irradiate a small field limited to the murine colorectum. The use of the clinic’s linear accelerator protected overall animal health and ensured their long-term survival. We found that the pathophysiology after 4 fractions of 8 Gy was similar to what is seen in biopsies of pelvic-organ cancer survivors, and that crypt degeneration was fraction-dependent and still ongoing at six weeks post-irradiation. Moreover, there was an increased number of macrophages in the mucosa at six weeks, possibly reflecting a lasting inflammatory activity. In the study for Paper II, we characterized the mouse model over a period of 30 weeks. We observed that crypt degeneration was still present at 30 weeks post-irradiation, as well as an increased presence of macrophages, possibly reflecting a chronic, low-grade inflammation. We also found that crypt fission, not cell proliferation, was the main repair mechanism after one week post-irradiation and onwards. In Papers III & IV, we studied the effect of bioprocessed oat bran, rich in dietary fiber, on radiation-induced damage to the intestine. In Paper III, we observed that the intake of dietary fiber modified the onset, timing, and intensity of radiation-induced pathophysiological processes when compared to a fiber-free diet. In the study for Paper IV, we observed that irradiation resulted in a long-lasting increase of serum cytokines indicating a chronic low-grade inflammation and that a fiber-free diet worsened this pro-inflammatory serum profile. In convergence, pelvic irradiation results in long-lasting, possibly chronic, pathophysiological changes in the intestines that may be driven by underlying low-grade inflammation. Nevertheless, even long after irradiation, the intestine attempts to repair itself via crypt fission. This mechanism as well as dietary interventions has the potential to modify the progression of the disease and may be explored further. Keywords: pelvic radiotherapy, intestinal inflammation, crypt fission, dietary fiber.
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| 7. |
- Patel, Piyush, et al.
(författare)
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Dietary oat bran reduces systemic inflammation in mice subjected to pelvic irradiation
- 2020
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 12:8
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Tidskriftsartikel (refereegranskat)abstract
- Patients undergoing radiotherapy to treat pelvic-organ cancer are commonly advised to follow a restricted fiber diet. However, reducing dietary fiber may promote gastrointestinal inflammation, eventually leading to deteriorated intestinal health. The goal of this study was to evaluate the influence of dietary fiber on radiation-induced inflammation. C57BL/6J male mice were fed a High-oat bran diet (15% fiber) or a No-fiber diet (0% fiber) and were either irradiated (32 Gy delivered in four fractions) to the colorectal region or only sedated (controls). The dietary intervention started at 2 weeks before irradiation and lasted for 1, 6, and 18 weeks after irradiation, at which time points mice were sacrificed and their serum samples were assayed for 23 cytokines and chemokines. Our analyses show that irradiation increased the serum cytokine levels at all the time points analyzed. The No-fiber irradiated mice had significantly higher levels of pro-inflammatory cytokines than the High-oat irradiated mice at all time points. The results indicate that a fiber-rich oat bran diet reduces the intensity of radiation-induced inflammation, both at an early and late stage. Based on the results, it seems that the advice to follow a low-fiber diet during radiotherapy may increase the risk of decreased intestinal health in cancer survivors. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
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| 8. |
- Sjöberg, Fei, et al.
(författare)
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Elastase as a potential biomarker for radiation-induced gut wall injury of the distal bowel in an experimental mouse model
- 2018
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 0284-186X .- 1651-226X. ; 57:8, s. 1025-1030
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Traditionally, elastase has been used to study exocrine activity of the pancreas in patients with chronic pancreatitis and cystic fibrosis, and calprotectin as a marker for gut-wall inflammation in patients with inflammatory bowel disease. The aim of the study was to find out whether elastase and calprotectin could be used as inflammatory markers for radiation-induced gut wall injury of the distal bowel.Material and methods: Adult male mice were exposed to two, three, or four fractions of 6Gy or 8Gy irradiation to the sigmoid and rectum of the large bowel, using a linear accelerator. Fecal samples were collected from mice at 1, 3, and 6 weeks post-irradiation. The fecal levels of elastase and calprotectin were analyzed using ELISA.Results: Three and 6 weeks after irradiation, we found a dose-effect relationship between dose of ionizing radiation and the fecal level of elastase; that is significantly higher levels of elastase were observed in mice that had received a high irradiation dose. We also found that irradiated mice hosted in the same cage had a comparable level (either high or low) of elastase. No significant differences were observed from the calprotectin data.Conclusions: We found a clear association between the dose of ionizing radiation to the distal colon and the level of elastase in the fecal samples.
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| 9. |
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| 10. |
- Voss, Ulrikke, et al.
(författare)
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Irradiation Induces Tuft Cell Hyperplasia and Myenteric Neuronal Loss in the Absence of Dietary Fiber in a Mouse Model of Pelvic Radiotherapy
- 2022
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Ingår i: Gastroenterology Insights. - : MDPI AG. - 2036-7422. ; 13:1, s. 87-102
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Tidskriftsartikel (refereegranskat)abstract
- Pelvic radiotherapy is associated with chronic intestinal dysfunction. Dietary approaches, such as fiber enrichment during and after pelvic radiotherapy, have been suggested to prevent or reduce dysfunctions. In the present paper, we aimed to investigate whether a diet rich in fermentable fiber could have a positive effect on radiation-induced intestinal damage, especially focusing on tuft cells and enteric neurons. Male C57BL/6 mice were fed either a purified non-fiber diet or the same purified diet with 5% or 15% oat fiber added, starting two weeks prior to sham-irradiation or irradiation with four fractions of 8 Gray. The animals continued on the diets for 1, 6 or 18 weeks, after which the gross morphology of the colorectum was assessed together with the numbers of enteric neurons, tuft cells and crypt-surface units. The results showed that dietary fiber significantly affected the intestinal morphometrics, both in the short and long-term. The presence of dietary fiber stimulated the re-emergence of crypt-surface unit structures after irradiation. At 18 weeks, the animals fed with the non-fiber diet displayed more myenteric neurons than the animals fed with the dietary fibers, but irradiation resulted in a loss of neurons in the non-fiber fed animals. Irradiation, but not diet, affected the tuft cell numbers, and a significant increase in tuft cells was found 6 and 18 weeks after irradiation. In conclusion, dietary fiber intake has the potential to modify neuronal pathogenesis in the colorectum after irradiation. The long-lasting increase in tuft cells induced by irradiation may reflect an as yet unknown role in the mucosal pathophysiology after pelvic irradiation. © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
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